System for mapping building interior with PDR and ranging and related methods

ABSTRACT

A system is for mapping an interior of a building. The system may include a mobile device having a PDR circuit configured to generate PDR positions as a user moves within the interior of the building, and a ranging circuit configured to generate ranging mapping data of the interior of the building as the user moves within the interior of the building. The system also may include a server configured to map the interior of the building and generate a location of the mobile device within the interior of the building based upon the PDR positions and the ranging mapping data from the mobile device.

TECHNICAL FIELD

The present disclosure relates to the field of location determination,and, more particularly, to mobile device location determination andmapping, and related methods.

BACKGROUND

A position of a person or object may be determined using a globalpositioning system (GPS) receiver, for example. However, to use a GPSreceiver, a GPS antenna coupled to the GPS receiver needs a line ofsight to GPS satellites. For increased accuracy, the number of GPSsatellites having a line of sight to the GPS antenna increases. In otherwords, position determining using a GPS receiver may not work indoors,for example, or other location where the GPS antenna does not have aline of sight to the sky.

In such GPS denied locations, a person or object may be tracked using aninertial measurement unit (IMU). An inertial measurement unit maycooperate with an accelerometer to calculate displacement, for example.More particularly, a determined acceleration may be first integratedover a time period to determine a velocity. The velocity may beintegrated over the time period to determine the displacement. In otherwords, a double integration is performed on the acceleration to arriveat the displacement.

Velocity drift due to accumulation of errors or noise may contribute toinaccuracies in determining the displacement over the time period.Additionally, gyroscope drift and bias in systems that include agyroscope, for direction, for example, may also contribute todisplacement inaccuracies over the time period. Moreover, performing thedouble integration of the determined acceleration over the time period,especially if the time period is relatively long or includes arelatively large amount of data samples from the accelerometer,typically introduces a relatively large error over the time period.

When the IMU is measured via a mobile device carried by a user, theprocess for location determining is known as pedestrian dead reckoning(PDR). In essence, the mobile device connects the dots from the lastknown position to attempt to determine the current location.

SUMMARY

Generally, a system is for mapping an interior of a building. The systemmay include at least one mobile device comprising a PDR circuitconfigured to generate a plurality of PDR positions as a user moveswithin the interior of the building, and a ranging circuit configured togenerate ranging mapping data of the interior of the building as theuser moves within the interior of the building. The system also mayinclude a server configured to map the interior of the building andgenerate a location of the at least one mobile device within theinterior of the building based upon the plurality of PDR positions andthe ranging mapping data from the at least one mobile device.

In some embodiments, the ranging circuit may comprise a Light Detectionand Ranging (LiDAR) circuit. The system may include a wireless basestation coupled to the server, and the at least one mobile device maycomprise a wireless transceiver communicating with the wireless basestation to send the plurality of PDR positions and the ranging mappingdata. For example, the wireless transceiver may comprise at least one ofan ultra high frequency (UHF) transceiver and a very high frequency(VHF) transceiver.

In particular, the server may be configured to correct an accumulatedPDR error in the plurality of PDR positions based upon the rangingmapping data. The at least one mobile device may comprise a geolocationdevice configured to generate an initial geolocation value, and theserver may be configured to generate the location of the at least onemobile device further based upon the initial geolocation value.

Also, the ranging mapping data may comprise a ranging point cloud, andthe at least one mobile device may be configured to convert the rangingpoint cloud into vector graphics data before sending to the server. Theat least one mobile device may comprise a plurality thereof. The servermay be configured to receive the ranging mapping data from each mobiledevice, and to generate the location of a given mobile device based uponthe ranging mapping data from the plurality of mobile devices.

Additionally, the PDR circuit may be configured to generate each PDRposition to comprise an x-position value, a y-position value, and az-position value. The PDR circuit may comprise at least one of anaccelerometer, a gyroscope, a magnetometer, and an altimeter.

Another aspect is directed to a method for operating a system formapping an interior of a building. The method may include operating aPDR circuit in at least one mobile device to generate a plurality of PDRpositions as a user moves within the interior of the building, andoperating a ranging circuit in the at least one mobile device togenerate ranging mapping data of the interior of the building as theuser moves within the interior of the building. The method may furtherinclude operating a server in communication with the at least one mobiledevice to map the interior of the building and generate a location ofthe at least one mobile device within the interior of the building basedupon the plurality of PDR positions and the ranging mapping data fromthe at least one mobile device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a system, according to the presentdisclosure.

FIG. 2 is another schematic diagram of the system of FIG. 1.

FIG. 3 is a schematic diagram of movement of the mobile device and PDRcalculations in an example embodiment of the system of FIG. 1.

FIG. 4 is a flowchart showing a method of operating a first exampleembodiment of the system of FIG. 1.

FIG. 5 is a diagram of ranging mapping data in an example embodiment ofthe system of FIG. 1.

FIG. 6 is a flowchart showing a method of operating a second exampleembodiment of the system of FIG. 1.

DETAILED DESCRIPTION

The present disclosure will now be described more fully hereinafter withreference to the accompanying drawings, in which several embodiments ofthe invention are shown. This present disclosure may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the present disclosure to those skilled in theart. Like numbers refer to like elements throughout.

In public safety applications, for example, the available approaches fordetermining a location for the mobile device may not be viable for whenthe user and associated mobile device enter a building. There have beensome approaches that try to address internal building locationdetermination by using various radio frequency (RF) signals, such asultra-wideband from outside the building, triangulation of beacons, andWiFi signal strength, etc. These approaches attempt to figure outlocation coordinates from time of flight of the RF signals or signalstrength and triangulation. The potential problem with these approachesis that they are sensitive to signals that are attenuated by walls. Thepresence of walls is not known ahead of time and walls can block RFsignals or greatly attenuate them.

Even if these technologies could provide location coordinates (e.g. GPScoordinates) of individual users, this simply determines the user'slocation (i.e. longitude and latitude) on the earth. Indeed, it ispossible to know someone's GPS coordinates and still not know how to getto them. In fact, inside a multi-story building, the GPS location doesnot include information on the route to reach the person.

Referring initially to FIGS. 1-2, a system 10 illustratively is formapping an interior of a building 16. The system 10 illustrativelyincludes a plurality of mobile devices 11 a-11 n, a wireless basestation 13 in communication with the plurality of mobile devices, and aserver 12 in communication with the wireless base station. The system 10is also for determining locations of the plurality of mobile devices 11a-11 n and respective users within the building 16.

For example, the wireless base station 13 may comprise a MASTR V BaseStation, as available from the Harris Corporation of Melbourne, Fla.,the present application's Applicant. Also, each of the plurality ofmobile devices 11 a-11 n may comprise a XL-185P handheld radio, asavailable from the Harris Corporation of Melbourne, Fla., the presentapplication's Applicant.

The server 12 illustratively comprises a processor 14, and a memory 15coupled thereto. For example, the server 12 may comprise a standalonecomputing device and/or assigned resources from a cloud computingplatform. As will be appreciated, in some applications, the wirelessbase station 13 may be geographically adjacent to the building 16, andthe server 12 may be geographically remote to the building and thewireless base station and be connected by, for example, a networkconnection, such as the Internet.

Each of the plurality of mobile devices 11 a-11 n illustrativelycomprises a processor 17, and a PDR circuit 20 coupled to the processorand configured to generate a plurality of PDR positions as a user moveswithin the interior of the building 16. The PDR circuit 20 is configuredto generate each PDR position to comprise an x-position value, ay-position value, and a z-position value. The PDR circuit 20 maycomprise one or more of an accelerometer 24, a gyroscope 25, amagnetometer 26, and an altimeter 27. The accelerometer 24, thegyroscope 25, the magnetometer 26, and the altimeter 27 are all shownwith dashed lines, and it should be appreciated that the PDR circuit 20may include any combination of these items.

Each of the plurality of mobile devices 11 a-11 n illustrativelyincludes a ranging circuit 21 coupled to the processor 17 and configuredto generate ranging mapping data of the interior of the building as theuser moves within the interior of the building. More specifically, theranging mapping data comprises a ranging point cloud.

In some embodiments, the ranging circuit 21 comprises a LiDAR rangingcircuit configured to generate LiDAR mapping data, i.e. a LiDAR pointcloud. In other embodiments, the ranging circuit 21 may comprisealternatively or additionally a RADAR circuit or a SONAR circuit.

Also, the ranging circuit 21 is configured to periodically sweepadjacent portions of the interior of the building 16, for example, 1 Hz.Also, for example, the ranging circuit 21 may provide a radial sweep ofdistance values spaced apart by 2 or more degrees.

In some embodiments, the ranging circuit 21 is configured to conductsweeps substantially simultaneously (i.e. ±100 ms) with generation of anew PDR position. The ranging mapping data relates to shapes andrespective positions of features of the interior of the building 16. Forexample, the features may include walls, openings in walls, andnon-structural barriers, etc.

Each of the plurality of mobile devices 11 a-11 n illustrativelyincludes a wireless transceiver 22 coupled to the processor 17 andcommunicating with the wireless base station 13 to send the plurality ofPDR positions, the ranging mapping data, and other data. For example,the wireless transceiver 22 may comprise one or more of an ultra highfrequency (UHF) transceiver (i.e. operating at the 300 MHz-3 GHz range),or a very high frequency (VHF) transceiver (i.e. operating at the 30-300MHz range) (e.g. Project 25 transceiver). Of course, these frequencybands are exemplary in nature and other frequency bands could be addedor used alternatively. Advantageously, the UHF and/or VHF transceiversmay have the capability to penetrate the structural features of thebuilding 16.

Each of the plurality of mobile devices 11 a-11 n illustrativelyincludes a geolocation device 23 coupled to the processor 17 andconfigured to generate an initial geolocation value (e.g. GPScoordinates). For example, the geolocation device 23 may comprise asatellite based location determining system, such as the GPS.

As will be appreciated, when users of the plurality of mobile devices 11a-11 n enter the building 16, the line of sight with the sky isimpaired, and the geolocation device 23 may be inoperable (i.e. the GPSdenied scenario). Indeed, the initial geolocation value may comprise thelast accurate position value generated before entry into the building16, providing an accurate building entry point for the user.

Because of this, the location of users of the plurality of mobiledevices 11 a-11 n in the building 16 is difficult to ascertain. This canbe particularly problematic in public safety applications, when thereare a large number of personnel in the building 16.

In the illustrated embodiment, the wireless base station 13 isconfigured to route the plurality of PDR positions, the ranging mappingdata, and the initial geolocation value from the plurality of mobiledevices 11 a-11 n to the server 12 via the wireless transceiver 22. Thewireless base station 13 is shown in dashed lines, and could be omittedin other embodiments where the plurality of mobile devices 11 a-11 nwould communicate directly with the server 12. In these embodiments, theserver 12 would also include a wireless transceiver, or operate, atleast in part, over a wireless link.

Once the server 12 has received the plurality of PDR positions, theranging mapping data, and the initial geolocation value, the server 12is configured to map the interior of the building 16 and generaterespective locations of the plurality of mobile devices 11 a-11 n withinthe interior of the building based upon at least the plurality of PDRpositions and the ranging mapping data, and in some embodiments,additionally further based upon the initial geolocation value.

Referring now additionally to FIGS. 3-4, the diagram 50 therein, and theflowchart 80 therein, the method for the server 12 to map the interiorof the building 16 and generate respective locations of the plurality ofmobile devices 11 a-11 n is now described. (Block 81). For a givenmobile device 11 a, the server 12 is configured to generate plurality ofPDR positions based upon measured relativistic inertial movement ((dX,dY)/dT) from the initial geolocation value (i.e. the last known accurategeolocation data). (Blocks 82-83, 86-87). Nevertheless, the accuracy ofthe plurality of PDR positions decreases linearly with the length of thesequence (i.e. an accumulated PDR error). Eventually, the calculatedcurrent location based solely upon the plurality of PDR positions willbecome inaccurate. Helpfully, the server 12 is configured to correct theaccumulated PDR error in the plurality of PDR positions based upon theranging mapping data (e.g. illustrated LiDAR mapping data). (Blocks84-85). In particular, the LiDAR mapping data provides an accuratebearing and distance to known features of the interior of the building16.

Referring now additionally to FIG. 5 and the diagram 51 therein, anexample of the LiDAR mapping data is shown. The LiDAR mapping dataincludes a LiDAR point cloud rendered in two-dimensional form. As can beseen, the walls of the interior of the building 16 are detected from themobile device 11 a-11 n. In fact, the accuracy of the interior featuresis improved as additional ones of the plurality of mobile devices 11a-11 n provide respective LiDAR mapping data of the same areas (i.e.effectively removing uncertainty in situational awareness for thebuilding 16). In other words, the server 12 is configured to accumulatethe LiDAR mapping data from the plurality of mobile devices 11 a-11 n toenhance the mapping data of the interior of the building 16.

Moreover, the server 12 is configured to store the path of travel forthe users of the plurality of mobile devices 11 a-11 n. In other words,in some embodiments, the server 12 is accumulating ranging data from theplurality of mobile devices 11 a-11 n. Similarly, the server 12 isconfigured to leverage this additional data to further sharpen themapping of the interior of the building 16. In fact, the server 12 isconfigured to generate a floorplan of the interior of the building 16.Further, since the PDR circuit 20 is configured to generate theplurality of PDR positions with a z value, the server 12 is configuredto generate multi-floor floor layouts. Of course, the server 12 is alsoconfigured to provide floor specific locations of the plurality ofmobile devices 11 a-11 n.

In some embodiments, the server 12 is configured to map the interior ofthe building 16 using a single mobile device 11 a-11 n. Of course, sincethe server 12 does not have the benefit of accumulating the rangingmapping data from multiple mobile devices, the server is configured tocorrelate the ranging mapping data with a priori known details of thebuilding (e.g. building blueprint, floor layout).

In some embodiments, the ranging mapping data and associated rangingpoint cloud are onerous in data size. In embodiments where the pluralityof mobile devices 11 a-11 n are operating on a narrowband UHF and/or VHFsystem, which includes bandwidth limitations, the task of transmittingthe ranging mapping data to the wireless base station 13 may beimpractical. Advantageously, the plurality of mobile devices 11 a-11 nmay be configured to convert the ranging point cloud into vectorgraphics data before sending to the server 12. (Blocks 88-90). Since thevector graphics data has a reduced data size, this may be more readilytransmitted over bandwidth limited communication protocols. For example,the conversion process may be based upon the “Potrace Tool”, asavailable from Peter Selinger on the SourceForge web-based service, butof course, other compression methods can be used. Of course, in someembodiments where high bandwidth wireless interfaces (e.g. WiFi,cellular) are available, the complete ranging point cloud is sent to theserver 12.

In the illustrated embodiment, the PDR circuit 20 and LiDAR circuit 21are collocated in the same mobile device 11 a-11 n (i.e. an integrateddevice). In other embodiments, the given mobile device 11 a-11 n maycomprise separate first and second communications devices. For example,the first device may comprise a bodycam or headcam format devicecarrying the ranging circuit 21, and the second communications devicecomprises a typical handheld radio device for communication with thewireless base station 13. In these embodiments, the first and secondcommunications devices may be coupled via a wired connection, or a localwireless connection, such as Bluetooth wireless communications, or IEEE802.11 WiFi, for example.

Referring now to FIG. 6, a flowchart 70 describes a method for operatinga system 10 for mapping an interior of a building 16. (Block 71). Themethod includes operating a PDR circuit 20 in at least one mobile device11 a-11 n to generate a plurality of PDR positions as a user moveswithin the interior of the building 16 (Block 72), and operating aranging circuit 21 in the at least one mobile device to generate rangingmapping data of the interior of the building as the user moves withinthe interior of the building. (Block 73). The method further includesoperating a server 12 in communication with the at least one mobiledevice 11 a-11 n to map the interior of the building 16 and generate alocation of the at least one mobile device within the interior of thebuilding based upon the plurality of PDR positions and the rangingmapping data from the at least one mobile device. (Blocks 75, 77).

Advantageously, the system 10 disclosed herein uses a fusion oftechnologies that, when combined with public safety radio systems, willallow system operators to know where users are located inside a buildingand exactly how to get to them. The combination of ranging basedSimultaneous localization and mapping (SLAM) and PDR will determine theprecise location of the user in location coordinates as well as generatea floor plan of the building as the user moves from room to room. Thedata from the sensors can be converted into location coordinates and avector graphic floorplan. This compressed data can be transported over anarrowband radio channel for the desired in-building penetration ofcommunication.

Many modifications and other embodiments of the present disclosure willcome to the mind of one skilled in the art having the benefit of theteachings presented in the foregoing descriptions and the associateddrawings. Therefore, it is understood that the present disclosure is notto be limited to the specific embodiments disclosed, and thatmodifications and embodiments are intended to be included within thescope of the appended claims.

That which is claimed is:
 1. A system for mapping an interior of abuilding, the system comprising: at least one mobile device comprising apedestrian dead reckoning (PDR) circuit configured to generate aplurality of PDR positions as a user moves within the interior of thebuilding, and a ranging circuit configured to generate ranging mappingdata of the interior of the building as the user moves within theinterior of the building and convert the ranging mapping data tographics data; and a server configured to map the interior of thebuilding and generate a location of said at least one mobile devicewithin the interior of the building based upon the plurality of PDRpositions and the graphics data from said at least one mobile device. 2.The system of claim 1 wherein said ranging circuit comprises a LightDetection and Ranging (LiDAR) circuit.
 3. The system of claim 1comprising a wireless base station coupled to said server; and whereinsaid at least one mobile device comprises a wireless transceivercommunicating with said wireless base station to send the plurality ofPDR positions and the graphics data.
 4. The system of claim 3 whereinsaid wireless transceiver comprises at least one of an ultra highfrequency (UHF) transceiver and a very high frequency (VHF) transceiver.5. The system of claim 1 wherein said at least one mobile devicecomprises a geolocation device configured to generate an initialgeolocation value; and wherein said server is configured to generate thelocation of said at least one mobile device further based upon theinitial geolocation value.
 6. The system of claim 1 wherein the rangingmapping data comprises a ranging point cloud.
 7. The system of claim 1wherein said at least one mobile device comprises a plurality thereof;and wherein said server is configured to receive the graphics data fromeach mobile device, and to generate the location of a given mobiledevice based upon the graphics data from the plurality of mobiledevices.
 8. The system of claim 1 wherein said PDR circuit is configuredto generate each PDR position to comprise an x-position value, ay-position value, and a z-position value.
 9. The system of claim 1wherein said PDR circuit comprises at least one of an accelerometer, agyroscope, a magnetometer, and an altimeter.
 10. A method for operatinga system for mapping an interior of a building, the method comprising:operating a pedestrian dead reckoning (PDR) circuit in at least onemobile device to generate a plurality of PDR positions as a user moveswithin the interior of the building; operating a ranging circuit in theat least one mobile device to generate ranging mapping data of theinterior of the building as the user moves within the interior of thebuilding and convert the ranging mapping data to graphics data; andoperating a server in communication with the at least one mobile deviceto map the interior of the building and generate a location of the atleast one mobile device within the interior of the building based uponthe plurality of PDR positions and the graphics data from the at leastone mobile device.
 11. The method of claim 10 wherein the rangingcircuit comprises a Light Detection and Ranging (LiDAR) circuit.
 12. Themethod of claim 10 further comprising operating a wireless transceiverin the at least one mobile device to communicate with a wireless basestation to send the plurality of PDR positions and the graphics data.13. The method of claim 12 wherein the wireless transceiver comprises atleast one of an ultra high frequency (UHF) transceiver and a very highfrequency (VHF) transceiver.
 14. The method of claim 10 furthercomprising operating a geolocation device in the at least one mobiledevice to generate an initial geolocation value, and operating theserver to generate the location of the at least one mobile devicefurther based upon the initial geolocation value.
 15. The method ofclaim 10 wherein the ranging mapping data comprises a ranging pointcloud.
 16. A server for mapping an interior of a building in cooperationwith at least one mobile device comprising a pedestrian dead reckoning(PDR) circuit configured to generate a plurality of PDR positions as auser moves within the interior of the building, and a ranging circuitconfigured to generate ranging mapping data of the interior of thebuilding as the user moves within the interior of the building andconvert the ranging mapping data to graphics data, the servercomprising: a processor and an associated memory configured to obtainthe plurality of PDR positions and the graphics data from the at leastone mobile device, and map the interior of the building and generate alocation of the at least one mobile device within the interior of thebuilding based upon the plurality of PDR positions and the graphics datafrom the at least one mobile device.
 17. The server of claim 16 whereinthe ranging mapping data comprises a Light Detection and Ranging (LiDAR)data.
 18. The server of claim 16 wherein the processor is configured towirelessly obtain the plurality of PDR positions and the graphics datafrom the at least one mobile device.
 19. The server of claim 16 whereinthe processor is configured to generate the location of the at least onemobile device further based upon an initial geolocation value therefrom.20. The server of claim 16 wherein the ranging mapping data comprises aranging point cloud.
 21. The system of claim 1 wherein the graphics datacomprises vector graphics data.
 22. The method of claim 10 wherein thegraphics data comprises vector graphics data.
 23. The server of claim 16wherein the graphics data comprises vector graphics data.